This invention relates to a latch device.
With sliding and hung window systems it is necessary to include a latch device (sometimes referred to as a xe2x80x9csash lockxe2x80x9d) to latch the window in a closed position. Over the years there have been many proposed types of window latches which aim to provide not only secure latching but also ease of operation. Despite the wide range of proposals which have been developed over the years there still exists the possibility of an improved latch device for sliding and hung window systems.
For example, with known latches for sliding and hung window systems forces can arise when the latching operation is carried out which causes the window to move off centre. This can result in sealing problems, distortion of window sash/rails, undesirable loadings applied to mounting hardware etc. These undesirable forces generated in the window generally arise from the use of a cam and keeper arrangement which is a typical latching mechanism for sliding and hung window systems.
Also there exists the need to ensure that that latching device prevents or renders difficult unauthorised access to be gained by external manipulation of the latch in order to release the latch tongue. To achieve this objective it is known to include a shroud or shield arrangement which prevents someone outside the window from engaging between, e.g. the window sashes, a thin tool to apply force to the latching tongue or cam to release it from the keeper. Such arrangements have not always been successful.
There also exists the possibility of improving the operative mechanism of such latches to not only improve the application of physical effort to operate the latch device but to additionally try and improve the aesthetic appeal of the latch. There is a move these days to have window hardware which, when visible, has a more pleasing appearance than has hitherto been thought to be necessary.
It is thus an object of the present invention to provide a latch device for sliding and hung window systems the latch device being of a construction which goes some way to achieving one or more of the above identified desired features.
Broadly, according to one aspect of the invention there is provided a latch device for sliding and hung window systems the latch device including a mounting base, a pair of counter-rotable cam elements coupled to the base, a lever cover slidingly engaged with the mounting base and a coupling mechanism which couples the lever cover to the cam elements whereupon in use a sliding movement of the lever cover is translated into pivotal movement of the cam elements.
The latch device further includes a keeper having a pair of cam engagement surfaces with which the cam elements are engagable to latch the mounting base to the keeper. Preferably the keeper includes a body having a pair of openings within each of which is located a said cam engagement surface.
Preferably the latch further includes a deadlocking means for whereby in use the cam elements can be deadlocked when in the latching position.
According to one preferred embodiment to the invention each cam element includes a follower which engages within a groove associated with the lever cover.
In a preferred form of the invention the latch device further includes detent means whereby the lever cover is releasably held in positions corresponding to the latch device being in the latching and unlatching positions.